The Atomic Force Microscope (AFM) is an instrument with huge impact on
modern research in the nanosciences and in nanotechnology. In AFM, a tip which is
sharp on a scale of nanometers or tens of nanometers, is scanning along the surface
which is imaged. A few among the large numbers of factors that potentially affect
the interaction between the tip and the surface were studied in the experimental
work that form this Thesis. Friction and elasticity measurements with AFM and the
approximation of the tip shape are discussed. Also the contribution of the imaging
environment is studied.
A commercial AFM was modified into a so called environmental-AFM (env-
AFM) , where the imaging conditions, such as pressure and humidity, can be controlled.
The modification was done so that a minimal intrusion to the original AFM
was made. The original setup of the AFM can be easily restored.
The elasticity of multiwalled carbon nanotubes (MWCNT) was measured by
studying the bending due to the van der Waals force of nanotubes that were placed
on microfabricated structures on silicon surfaces. The measurements were in agreement
with the theoretical model that takes into account the competition between the
van der Waals force between carbon nanotube (CNT) and surface and the restoring
elastic force of the nanotube.
Lateral force (LF) and pull-off distance measurements as a function of humidity
on a hydrophilic silicon showed a maximum at the relative humidity (RH)
slightly above 30 %. The coincidence of the maximum for both measurements was
shown for the first time in this work.
The precise shape of the AFM tip was determined with MWCNTs and micro
fabricated steps for different kind of tips in contact and in tapping mode.

fi

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Verkkokirja (84 s.)

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eng

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University of Jyväskylä

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Research report / Department of Physics, University of Jyväskylä;0075-465X ;no. 8/2011